Now, the flooded depths of an abandoned iron mine in southwestern Wisconsin have yielded yet another novelty: microbes that produce nanometer-scale crystals of extraordinary length. The discovery of the willowy microscopic crystals may open a broad new window to human understanding of biomineralization, the same process that produces bone, teeth and shell, some of nature's toughest and most intriguing biological materials.
Writing in the March 12, 2004 issue of the journal Science, a team of scientists from the University of California, Berkeley and the University of Wisconsin-Madison describe not only the discovery of the willowy microbe-made crystalline structures, but also the process by which they are produced.
"The crystals are unusual primarily in their large aspect ratio. They are only a couple of nanometers wide and up to about ten microns long. Because they are over a thousand times longer than they are wide, they can be visualized as having the same proportions as human hair," says Jill Banfield, a UC Berkeley professor of earth and planetary science and the senior author of the Science paper.
Taking the discovery an important step further, the Wisconsin-California team used X-rays generated by the storage ring at the UW-Madison Synchrotron Radiation Center, and a novel microscope, to chart the chemical processes that govern the formation of the crystals, revealing a production template that could be at the heart of the biomineralization process.
"The key is finding a template," says Gelsomina De Stasio, a UW-Madison professor of physics who, with Clara S. Chan of UC Berkeley, was a lead author of the Science paper. "How were these crystals formed?"